This application concerns both experimental and theoretical research on the mechanism of pathological vocal-cord vibrations as well as new progress in the diagnosis and medical treatment of voice disorders. The proposed investigations are based primarily on the theoretical model of the normal vocal cords published by Ishizaka and Flanagan (15) and on the preliminary experiments on asymmetric vibrations of extirpated larynges presented by Isshiki at the International Congress of Phoniatrics and Logopedics in Buenos Aires (21). The specific aims of the project are: (1) the experimental investigation of the classification of vibratory patterns of pathological vocal cords, (2) the theoretical modeling of pathological vocal-cord vibration and voice production, and (3) the acoustic detection of laryngeal pathology. Both theoretical and experimental studies will be required to accomplish these objectives.